High Automation of Thermo Scientific FlashSmart CHN/O Analyzer using the MultiValve Control (MVC) Module

Each analytical circuit accepts its own autosampler. In this way the system copes effortlessly with the laboratory requirements such as accuracy, day to day reproducibility and high sample throughput.

The MVC Module ensures very low helium consumption by switching from helium to nitrogen or argon gas, when the instrument is in Stand-By Mode. In this way the cost of analysis significantly reduced.

Key WordsAccuracy, Automation, CHN, Flash Combustion, Organic Chemistry, Oxygen, Unattended Analysis

GoalTo demonstrate the performance of the MultiValve Control (MVC) Module on the FlashSmart Elemental Analyzer for CHN/O determinations.

Introduction Carbon, nitrogen and hydrogen determination, by combustion analysis, and oxygen determination by pyrolysis are commonly used for the characterization of raw and final products in pharmaceutical, cosmetics, universities and material industries for quality control and R&D purposes. The use of an accurate and automated analytical technique, allowing the fast analysis with excellent reproducibility, is however essential.

The Thermo Scientific™ FlashSmart™ Elemental Analyzer (Figure 1) is equipped with two totally independent furnaces allowing the installation of two analytical circuits that can be used sequentially and are completely automated through the Thermo Scientific™ MultiValve Control (MVC) Module (Figure 2).

TN

42257

TECHNICAL NOTE

Dr. Liliana Krotz, Dr. Francesco Leone and Dr. Guido Giazzi Thermo Fisher Scientific, Milan, Italy

Figure 1. Thermo Scientific FlashSmart Analyzer.

MethodsFor CHN determination, the FlashSmart Analyzer operates with the dynamic flash combustion of the sample. Samples are weighed in tin containers and introduced into the combustion reactor (left furnace) from the Thermo Scientific™ MAS Plus Autosampler with oxygen. After combustion, the resulted gases are conveyed by a helium flow to the catalyst, a layer filled with copper and silvered cobaltous-cobaltic oxide, then swept through a GC column that provides the separation of the combustion gases. Finally, they are detected by a Thermal Conductivity Detector (TCD). The total run time is about 7 minutes. (Figure 3).

Figure 2. Thermo Scientific MultiValve Control Module.

Analytical Conditions

Reactor Temperature 950 °C

GC Oven Temperature 75 °C

Helium Carrier Flow 140 ml/min

Helium Reference Flow 100 ml/min

Oxygen Flow 250 ml/min

Oxygen Injection Time 5 sec

Sample Delay 12 sec

Total Run Time 480 sec

For oxygen determination, the system operates in pyrolysis mode. Samples are weighed in silver containers and introduced into the pyrolysis reactor (right furnace) from the MAS Plus Autosampler. The reactor contains nickel coated carbon maintained at 1060 °C.

The oxygen present in the sample, combined with the carbon, forms carbon monoxide which is then chromatographically separated from other products and detected by the TCD detector (Figure 3). A complete report is automatically generated by the Thermo Scientific™ EagerSmart Data Handling Software and displayed at the end of the analysis.

Figure 3. FlashSmart CHN/O configuration.

TCD EagerSmartH2O Trap

GC Column

Reduction

Oxidation

Oxygen Helium

Autosampler

Pyrolysis

Helium

Autosampler

CHN Configuration Oxygen Configuration

GC Column

ResultsTypical analytical tests were performed for CHN and oxygen configuration during several non-consecutive days, to evaluate the repeatability, accuracy and the stability of the system when the configuration is switched from CHN to oxygen, and vice versa. The experimental data obtained were compared with the theoretical values and the acceptable range according to the technical specification of the system.

At the end of each day the instrument remains in Stand-By Mode to reduce the consumption of helium. The Auto-Ready function was activated through the EagerSmart Data Handling Software to automatically wake-up the Analyzer following day and prepare for analysis.

On day 1, the instrument was calibrated for CHN and for oxygen with Acetanilide standard, using K factor as the calibration method. Then three runs of CEDFNI (cyclohexanone 2,4-dinitrophenylhydrazone) for CHN and Acetanilide for oxygen determination were performed as unknown to verify the calibration.

Table 1 shows the sequence of analysis for CHN determination. Table 2 shows the sequence of analysis for oxygen determination.

The theoretical values and the acceptable range according to the technical specification of the system of CEDFNI are 20.14 N% (±0.20), 51.79 C% (± 0.30), 5.07 H% (±0.10), while for Acetanilide the value is 11.84 O% (±0.12).

Figure 4. FlashSmart CHN and Oxygen internal circuits.

GC Column and TCD Detector

Adsorber Filter and OvenFurnaces

The EagerSmart Data Handling Software page managing the MVC module. Figure 5 shows in the lower part how to switch from left to right furnace to pass from CHNS determination by combustion to oxygen analysis by pyrolysis. The upper of the page indicates how to switch from helium carrier gas to nitrogen or argon gas when the instrument is not used for analysis.

Figure 5. The MVC Module Management page on the EagerSmart Data Handling Software.

The pneumatic circuits for CHN and oxygen determination are setup simultaneously in the same system which allows the MVC Module to automatically switch between the reactors through the EagerSmart Software without any operational action by the user. Figure 4 shows the internal parts of the FlashSmart Analyzer.

Table 1. CHN sequence of analysis for day 1.

Run Sample name Day/Month Injection Time Type Weight (mg) N% C% H%

1 Tin container 16/02 15:58 Blank

2 Acetanilide 16/02 16:07 By-Pass

Theoretical values

3 Acetanilide 16/02 16:15 STD 2.491 10.36 71.09 6.71

4 Acetanilide 16/02 16:23 STD 2.733 10.36 71.09 6.71

5 Acetanilide 16/02 16:32 STD 3.007 10.36 71.09 6.71

Experimental data

6 CEDFNI 16/02 16:40 UNK 2.528 19.98 51.86 5.05

7 CEDFNI 16/02 16:49 UNK 2.464 19.95 51.88 5.05

8 CEDFNI 16/02 16:57 UNK 2.542 19.95 51.84 5.05

Theoretical values

CEDFNI 20.14 51.79 5.07

Accepted range (±)

CEDFNI 0.20 0.30 0.10

Table 2. Oxygen sequence of analysis for day 1.

Run Sample name Day/Month Injection Time TypeWeight

(mg)O%

1Silver

container16/02 17:08 Blank

2 Acetanilide 16/02 17:16 By-Pass

Theoretical values

Accepted range

3 Acetanilide 16/02 17:24 STD 1.995 11.84 ±0.12

4 Acetanilide 16/02 17:33 STD 1.603 11.84 ±0.12

5 Acetanilide 16/02 17:41 STD 1.810 11.84 ±0.12

Experimental data

6 Acetanilide 16/02 17:50 UNK 1.732 11.77

7 Acetanilide 16/02 17:58 UNK 1.687 11.84

8 Acetanilide 16/02 18:06 UNK 1.789 11.81

Acetanilide and CEDFNI for CHN, and Acetanilide for oxygen determination were analyzed as unknown without recalibration of the instrument, in four series each day with each series run in duplicate across 40 days. After each series of CHN, the instrument was automatically switched to oxygen determination using the MVC Module. Afterwards, the instrument returned to CHN determination. The switching between CHN and O configurations was performed to evaluate the data and the stability of the system. The Analyzer was stable and ready for analysis in only ten minutes after switching configurations.

Table 3 shows the CHN average data obtained, while Table 4 shows the oxygen average data. In each configuration, 208 analyses were performed. All results are acceptable and according to the specification of the instrument, indicating no effect due to configuration switching using the MVC Module from combustion to pyrolysis, or vice versa confirming the stability of the FlashSmart Analyzer.

Table 3. CHN average data.

Day / Month Standard No. Runs N% RSD% C% RSD% H% RSD%

17/02Acetanilide 8 10.40 0.59 71.06 0.16 6.70 0.44

CEDFNI 8 20.20 0.30 51.85 0.14 5.07 0.27

18/02Acetanilide 8 10.35 0.63 71.18 0.19 6.73 0.43

CEDFNI 8 20.17 0.23 51.91 0.14 5.08 0.24

19/02Acetanilide 8 10.32 0.39 71.13 0.18 6.72 0.40

CEDFNI 8 20.14 0.48 51.90 0.12 5.08 0.41

22/02Acetanilide 8 10.39 1.08 71.27 0.69 6.78 0.77

CEDFNI 8 20.24 0.46 51.86 0.09 5.09 0.13

23/02Acetanilide 8 10.37 0.49 71.18 0.11 6.75 0.38

CEDFNI 8 20.22 0.63 51.91 0.10 5.09 0.31

24/02Acetanilide 8 10.34 0.51 71.12 0.22 6.74 0.56

CEDFNI 8 20.08 0.28 51.97 0.13 5.08 0.29

25/02Acetanilide 8 10.38 0.51 71.30 0.08 6.73 0.42

CEDFNI 8 20.16 0.54 51.99 0.20 5.08 0.22

26/02Acetanilide 8 10.37 0.51 71.30 0.24 6.71 0.38

CEDFNI 8 20.09 0.49 51.97 0.25 5.07 0.34

23/03Acetanilide 8 10.43 0.28 71.25 0.16 6.74 0.67

CEDFNI 8 20.24 0.26 52.06 0.17 5.08 0.49

24/03Acetanilide 32 10.42 0.32 71.02 0.15 6.71 0.37

CEDFNI 32 20.16 0.36 51.79 0.12 5.06 0.25

Table 4. Oxygen average data.

Day / Month Standard No. Runs O% RSD%

17/02 Acetanilide 16 11.82 0.28

18/02 Acetanilide 16 11.86 0.37

19/02 Acetanilide 16 11.85 0.29

22/02 Acetanilide 16 11.88 0.33

23/02 Acetanilide 16 11.86 0.31

24/02 Acetanilide 16 11.89 0.28

25/02 Acetanilide 16 11.87 0.36

26/02 Acetanilide 16 11.84 0.34

23/03 Acetanilide 16 11.88 0.45

24/03 Acetanilide 64 11.86 0.36

To evaluate the linearity of the system, pure organic compounds with a range of CHN/O amounts were chosen. Instrument calibration was performed with Acetanilide (10.36 N%. 71.09 C%, 6.71 H%, 11.84 O%), Atropine (4.84 N%, 70.56 C%, 8.01 H%, 16.59 O%) and CEDFNI (20.14 N%, 51.79 C%, 5.07 H%, 23.00 O%) standards (STD) using Linear Fit as the calibration method. For CHN determination, the standard weight was 2-3 mg, while for oxygen determination the weight was 1-1.5 mg.

After the CHN sequence, the instrument switched to oxygen configuration and the oxygen sequence of analyses was performed. The switch is automated by the EagerSmart Data Handling Software.

Pure organic standards in a large range of concentration were selected and analyzed as unknown (UNK) to evaluate the calibration, repeatability and accuracy of the data obtained.

Table 5 shows the theoretical percentages of the pure organic standards analyzed as unknown and the accepted range according to the technical specification of the system. Table 6 shows the experimental data obtained. Each standard was analyzed in triplicate.

All data are acceptable and no effect was observed when changing the sample or switching between configurations using the MVC Module.

Table 5. Theoretical values and accepted range of pure organic standards.

StandardNitrogen Carbon Hydrogen Oxygen

% Range (±) % Range (±) % Range (±) % Range (±)

Acetanilide 10.36 0.10 71.09 0.30 6.71 0.10 11.84 0.12

Aspartic Acid 10.52 0.10 36.09 0.28 5.30 0.08 48.08 0.30

Atropine 4.84 0.07 70.56 0.30 8.01 0.10 16.59 0.18

BBOT* 6.51 0.10 72.53 0.30 6.09 0.10 7.43 0.10

Benzoic Acid N/A N/A 68.85 0.30 4.95 0.08 26.20 0.25

CEDFNI** 20.14 0.20 51.79 0.30 5.07 0.08 23.00 0.22

Methionine 9.39 0.10 40.25 0.30 7.43 0.10 21.45 0.20

L-Cystine 11.66 0.12 29.99 0.28 5.03 0.08 26.63 0.25

Nicotinamide 22.94 0.22 59.01 0.30 4.95 0.08 13.10 0.14

Sulfanilamide 16.27 0.16 41.84 0.30 4.68 0.07 18.58 0.20

* BBOT: 2,5-Bis (5-tert-butyl-benzoxazol-2-yl) thiophene **CEDFNI: cyclohexanone 2,4-dinitrophenylhydrazone

Table 6. Repeatability and accuracy of pure organic standards.

StandardNitrogen Carbon Hydrogen Oxygen

% RSD% % RSD% % RSD% % RSD%

Acetanilide

10.41 71.09 6.73 11.89

0.3910.35 0.44 71.34 0.18 6.74 0.15 11.81

10.44 71.21 6.75 11.81

Aspartic Acid

10.45 36.18 5.31 47.99

0.1310.45 0.06 36.26 0.11 5.33 0.22 48.12

10.44 36.24 5.33 48.05

Atropine

4.91 70.60 8.04 16.73

4.88 0.31 70.73 0.10 8.04 0.00 16.63 0.30

4.89 70.62 8.04 16.67

BBOT

6.54 72.65 6.12 7.41

6.52 0.31 72.64 0.01 6.09 0.84 7.38 0.28

6.56 72.63 6.02 7.42

Benzoic Acid NA

68.99 4.91 26.32

NA 68.83 0.14 4.99 0.81 26.20 0.23

69.01 4.96 26.26

CEDFNI

20.15 51.87 5.09 22.85

20.11 0.20 51.90 0.20 5.09 0.11 23.00 0.42

20.07 52.06 5.10 22.82

Methionine

9.40 40.38 7.48 21.46

9.46 0.32 40.42 0.34 7.50 0.15 21.41 0.19

9.44 40.26 7.48 21.38

L-Cystine

11.61 29.93 5.10 26.60

11.64 0.13 29.93 0.04 5.09 0.11 26.76 0.11

11.62 29.91 5.10 26.68

Nicotinamide

23.02 59.06 4.97 13.03

22.88 0.31 59.07 0.02 4.97 0.00 12.98 0.24

22.93 59.08 4.97 12.97

Sulfanilamide

16.17 41.77 4.69 18.52

16.21 0.21 41.85 0.16 4.68 0.21 18.52 0.14

16.24 41.91 4.70 18.48

Additionally, two tests were performed to show the accuracy and repeatability of organic compounds with high nitrogen and carbon content. For high nitrogen determination, 2-3 mg of Urea standard (46.65 N%, 20 C%, 6.71 H%) was analyzed in triplicate as unknown.

For high carbon determination, the calibration were performed with 2-3 mg of Acetanilide (10.36 N%, 71.09 C%, 6.71 H%) using K factor as the calibration method. Following, about 2 mg of different high carbon content standards were analyzed in triplicate as unknown.

Table 7. CHN data of Urea (46.65 N%, 20 C%, 6.71 H%).

Run W (mg)Nitrogen Carbon Hydrogen

% RSD%Acceptable

range% RSD%

Acceptable range

% RSD%Acceptable

range

1 2.545 46.79

0.15 46.36 – 46.96

20.15

0.23 19.80 – 20.20

6.71

0.22 6.61 – 6.812 2.422 46.66 20.09 6.74

3 2.194 46.69 20.18 6.73

Table 8. CHN theoretical data of high carbon content standards.

StandardNitrogen Carbon Hydrogen

% Acceptable range % Acceptable range % Acceptable range

Tocopherol Nicotinate 2.61 ± 0.07 78.46 ± 0.30 9.97 ± 0.10

Polyethylene N/A N/A 85.70 ± 0.30 14.30 ± 0.15

Polystyrene N/A N/A 92.30 ± 0.30 7.70 ± 0.10

Antracene N/A N/A 94.34 ± 0.30 5.66 ± 0.09

Fluorene N/A N/A 93.81 ± 0.30 6.03 ± 0.10

The calibration was performed with 2.5-3 mg of Imidazole standard (41.15 N%, 52.93 C%, 5.92 H%) using K factor as the calibration method. Table 7 shows the experimental CHN data of Urea in comparison to the theoretical values and the acceptable range. All data are inside the technical specification of the system and show excellent accuracy and precision.

Table 8 shows the CHN theoretical percentages of the standards analyzed as unknown and the acceptable range. Table 9 shows the experimental data obtained which are inside the technical specification of the system and demonstrate excellent accuracy and precision of the Analyzer.

ConclusionThe FlashSmart Analyzer is the optimal solution for the analysis of CHN/O in terms of accuracy, reproducibility, automation, speed of analysis and cost per analysis. All data showed were obtained with an acceptable repeatability and no matrix effect was observed when changing the configuration.

The MultiValve Control (MVC) Module performs the following functions:

• Automated switch from the left channel to the right channel, or vice versa.

• Reduced helium (or argon) consumption by switching from helium (or argon) to nitrogen or argon when the system is in Stand-By Mode.

• Optionally insert, using the EagerSmart Data Handling Software, an external command, for example an actuator for a gas sampling valve.

Find out more at thermofisher.com/OEA

For Research Use Only. Not for use in diagnostic procedures. © 2016 Thermo Fisher Scientific Inc. All rights reserved. All trademarks are the property of Thermo Fisher Scientific and its subsidiaries unless otherwise specified. TN42257-EN 0716

The dual analytical configuration capability using the MVC Module allows you to:

• Automatically and rapidly switch from one configuration to another, increasing laboratory productivity.

• Gain continuous operation of the system by using one reactor for CHNS on the left furnace and one reactor on the right furnace.

• Fully control the workflow by the EagerSmart Data Handling Software.

The all-in-one FlashSmart Analyzer hardware, autosamplers and software can be used for other combinations such CHNS/O, CHN/S, CHNS/CHNS, CHN/CHN, NC/S, N-Protein/S, etc. This can be achieved by only changing the consumables as the hardware and software are complete, illustrating the all-in-one nature of the Analyzer.

Run StandardNitrogen Carbon Hydrogen

% RSD% % RSD% % RSD%

1

Tocopherol Nicotinate

2.59 78.57 10.01

2 2.65 1.33 78.25 0.22 10.02 0.10

3 2.59 78.53 10.03

4

Polyethylene

N/A 85.89 14.26

5 N/A N/A 85.82 0.11 14.35 0.33

6 N/A 85.70 14.33

7

Polystyrene

N/A 92.16 7.74

8 N/A N/A 92.22 0.04 7.72 0.33

9 N/A 92.17 7.77

10 N/A 94.22 5.67

11 Antracene N/A N/A 94.43 0.12 5.66 0.18

12 N/A 94.24 5.65

13

Fluorene

N/A 93.84 6.05

14 N/A N/A 93.87 0.11 6.07 0.19

15 N/A 94.03 6.07

Table 9. CHN experimental data of high carbon content standards.